Locomotive control system



Oct. 10, 1939. T. L. WEYBREW 2,175,862

LOCOMOTIVE CONTROL SYSTEM Filed Jan. 28, 1958 4 JUU'1 fi' l'l l'l l l l'l l l l- WITNESSES: INVENTOR WA. xmzzm Me/berf L Vl eybrew TTOR I Patented Oct. 10, 1939 UNITED STATES PATENT OFFICE LOCOMOTIVE CONTROL SYSTEM Pennsylvania Application January 28, 1938, Serial No. 187,534

'7 Claims.

My invention relates, generally, to locomotive control systems and, more particularly, to systems for controlling the operation of locomotives of the self-propelled type, as, for example, Dieselelectric locomotives.

The proper control of the power developed by the prime mover of a self-propelled vehicle is an important consideration. The limited installed horsepower requires full utilization of that available. The delivered output is continually changing due to engine condition and temperature, as well as altitude, atmospheric conditions, fuel, and similar considerations. Since none of the foreu going are controllable, the electrical control systern must be designed to transmit the maximum output at all times and under all conditions.

One type of electrical control previously utilized is known as differential-exciter control and another type is known as torque control. There are certain inherent advantages in the differential-exciter control and in the torque control schemes for governing the engine loading on comotives and rail cars. Difierential-exciter control provides inherent and automatic reduction of the torque required from the engine at the lower engine speeds. Torque control provides complete loading and maximum torque at all speeds regardless of machine temperature. It also reduces the load to compensate for engine condition. The reduction of torque by differential-exciter control is particularly desirable in oil engines to avoid high cylinder pressures at low engine speeds.

An object of my invention, generally stated, is to provide a locomotive control system which shall be simple and efiicient in operation and which may be economically manufactured and installed.

A more specific object of my invention is to provide a locomotive control system which shall have certain of the foregoing advantages of both the diiferential-exciter and the torque control systems. I

Another object of my invention is to provide for transferring the control of an oil-electric locomotive from diiferential-exciter control to torque control while the locomotive is in operation.

Other objects of my invention will be explained more fully hereinafter or will be apparent to those skilled in the art.

In accordance with on embodiment of my invention the load on the Diesel engine is controlled by a differential exciter while the engine is operating under a predetermined speed, thereby obtaining the advantages of differential-exciter control at low engine speeds. When the engine is operating above a predetermined speed, the loading is governed by a torque control system which permits the engine to operate at maximum efiiciency. In this manner, the principal 5 advantages of both systems of control are obtained to improve the performance of the locomotive.

For a fuller understanding of the nature and objects of my invention, reference may be had to the following detailed description, taken in conjunction with the accompanying drawing, in which the single figure is a diagrammatic view of a control system embodying the invention.

Referring to the drawing, the system shown therein comprises a main generator 9 having an armature winding Iii, a separately excited field winding [I and a starting field winding l2; an exciter 13 having an armature winding I4, a separately excited field winding [5 and a differential field winding IS; an auxiliary generator I! having an armature winding I 8 a series field winding l9 and a shunt field winding 2| an internal combustion engine 22, which may be of the Diesel type, for driving the foregoing machines; a motor 23, which is supplied with current from the generator 5 for propelling a locomotive or vehicle (not shown) a battery a voltage regulator 25 for regulating the voltage of the auxiliary generator I! during a portion of the operating cycle; a regulator 26 for regulating the main generator field current to control the load on the engine during the remainder of the operating cycle; a pair of switches 21 and 28 for transferring the control of the engine loading from the differential exciter to the regulator 26; a contactor 29 which cooperates with the regulator 26 to control the generator field current; a pair of switches 3| and 32 for connecting the generator [0 across the battery 24 to start the engine 22, a throttle 33 for selectably controlling the speed of the engine; a pair of switches 35 and 35 actuated by the throttle 33 in accordance with the selected speed of the engine; a contactor 36 for controlling the energization of the field winding P5 of the exciter 13; control switches 31 and 38 and a push-button switch 39 for starting the engine 22.

In order that the functioning of the foregoing apparatus may be more clearly understood, the operation of the system will now be described in more detail.

Assuming that it is desired to start the engine 22, the control switch 31 is first closed to connect the battery 24 to the control circuits, after which the push-button switch 39 is closed to energize the actuating coils of the switches 3i and 32, thereby closing these switches to connect the generator armature iii and starting field I2 across the battery 2 to crank the engine 22. After the engine has started the push-button switch 39 is released, which permits the switches 3i and 32 to open, and the control switch 38 is closed.

The closing of the switch 38 energized the actuating coil of the switch 21 through interlocks il, Q2 and 33 on the switches 3|, 32 and 28, respectively, thereby closing the switch 27, which connects the operating coils of the voltage regulator 25 across the armature of the auxiliary generator ii and also connects the contact members of the regulator in the shunt field circuit to vary the field current by means of resistors 44, 45 and 46. In this manner, the voltage of the auxiliary generator is so controlled by the regulator 25 that the auxiliary generator may be utilized to supply power for the auxiliary equipment on the locomotive, such as a compressor motor and a fan motor (not shown) as well as for charging the battery 24 while the locomotive is not in operation.

If it is desired to operate the locomotive at a slow speed, the throttle 33 is opened sufiiciently to cause the engine 22 to run at approximately half speed, at which position the throttle switch 34 is closed. The closing of the throttle switch 3 3 energizes the actuating coil of the switch 36, thereby closing this switch to connect the field winding 55 of the exciter it across the battery E l.

The energization of the exciter field winding 55 causes the exciter to generate suincient voltage to energize the field winding ill of the main generator 9, thereby causing this generator to generate current for operating the motor 23 which drives the locomotive. In this manner, power for operating the locomotive is produced by the engine 22 and electrically transmitted to the wheels of the locomotive.

As explained hereinbeiore, the load on the engine during slow speed operation is controlled by the differential field winding i5 on the exciter I3. The differential field winding is so connected in the generator armature circuit that an increase in the generator current decreases the exciter voltage which, in turn, decreases the excitation of the generator and lowers the output of the generator, thereby decreasing the load on the engine. In this manner, the load on the engine is so controlled that the engine torque is automatically reduced at the lower engine speeds, thereby avoiding high cylinder pressures in the engine.

In order to obtain the advantages of the system of control known as torque control during higher speed operation, I have provided for automatically transferring the load control from the differential exciter to the regulator 26 when the engine throttle is set for high speed operation. When the throttle is set for approximately full speed, the throttle switch 35 is closed to energize the actuating coil of the transfer switch 28, thereby closing this switch to connect the operating coils of the regulator 26 across the auxiliary generator ii and place the excitation of the main generator 9 under the control of the regulator 2%.

The closing of the transfer switch 28 opens the interlock to deenergize the coil of the switch 2'1 which causes this switch to open, thereby making the voltage regulator 25 ineffective. The field winding 2! on the auxiliary generator I! is now connected across the battery 24 through a portion of a resistor 41 and contact members 48 on the switch 28. Therefore, the voltage of this generator will now be proportional to the speed of the engine and this voltage may be utilized as an indication of the engine speed.

Since the operating coil of the regulator 26 is connected across the auxiliary generator through contact members of the switch 28, the regulater is responsive to the voltage of the auxiliary generator, which is proportional to the engine speed. The contact members of the regulator 2E control the operation of contractor 29, which in turn, controls the current in the field winding ii of the generator Q, thereby controlling the output of the generator. Thus, if the engine slows down in speed, the regulator 28 functions to decrease the output of the generator, which permits the engine speed to increase to normal. In this manner, the torque on the engine is so regulated that the engine is permitted to operate at normal speed regardless of the condition of the engine.

From the foregoing description it is apparent that I have provided a control system which has the principal advantages oiboth differentialcxciter control and torque control. Thus, when the engine is operating at low speeds, the engine loading is governed by differential-exciter control, which is more advantageous during slow speed operation. When operating at high speeds, the engine loading is governed by the torque controlling relay, thereby obtaining the advantages of the torque control system for high speed operation.

Since numerous changes may be made in the construction, and different embodiments of the invention be made without departing from the spirit and scope thereof, it is intended that all matter contained in the above description or shown in the accompany drawing shall be interpreted as illustrative and not in a limiting sense.

I claim as my invention:

1. In a locomotive control system, in combination, a generator, an exciter for the generator, an engine for driving said machines, means for controlling the speed of the engine, means on said exciter for controlling the load on the engine, regulating means for also controlling the load on the engine, and means associated with the means for controlling the speed of the engine for so controlling the operation of said regulating means that it is eiieotive only above a predetermined engine speed.

2. In a locomotive control system, in combination, a generator, an exciter for the generator, an engine for driving said machines, means for controlling the speed of the engine, difierential field means on said exciter for controlling the load on the engine, regulating means for also controlling the load on the engine, and means associated with the means for controlling the speed of the engine for so controlling the operation of said regulating means that it is eifective only above a predetermined engine speed.

3. In a locomotive control system, in combination, a generator, an exciter for the generator, an engine for driving said machines, means for controlling the speed of the engine, diiferential field means on said exciter for controlling the load on the engine, regulating means for also controlling the load on the engine, and means responsive to the speed of the engine for transferring the load control from the differential exciter to the regulating means.

4. In a locomotive control system, in combination, a generator, an exciter for the generator, an auxiliary generator, an engine for driving said machines, means for controlling the speed of the engine, differential field means on said exciter for controlling the load on the engine, regulating means responsive to the voltage of the auxiliary generator for also controlling the load on the engine, and means associated with the means for controlling the speed of the engine for making said regulating means effective only above a predetermined engine speed.

5. In a locomotive control system, in combination, a generator, an exciter for the generator, an auxiliary generator, an engine for driving said machines, means for selectably controlling the speed of the engine, differential field means on said exciter for controlling the exciter voltage to control the load on the engine, regulating means responsive to the voltage of the auxiliary generator for regulating the generator field current to control the load on the engine, and means responsive to the position of the means for controlling the engine speed for making said regulating means efiective only above a predetermined engine speed.

6. In a locomotive control system, in, combination, a generator, an exciter for the generator, an auxiliary generator, an engine for driving said machine, means for selectably controlling the speed of the engine, differential field means on said exciter for controlling the exciter voltage to control the load on the engine, regulating means responsive to the voltage of the auxiliary generator for regulating the generator field current to control the load on the engine, and switching means actuated by the means for controlling the engine speed for transferring the load control from the differential exciter to said regulating means when the engine is operating at a predetermined speed.

7. In a locomotive control system, in combination, a generator, an exciter for the generator, an auxiliary generator, an engine for driving said machines, means for selectably controlling the speed of the engine, a difierential field winding on said exciter energized by the generator armature current for controlling the exciter voltage to control the load on the engine, means for regulating the voltage of the auxiliary generator while the engine load is controlled by the differential exciter, switching means actuated by the means for controlling the engine speed for making said regulating means ineffective, additional regulating means responsive to the voltage of the auxiliary generator for regulating the generator field current to control the load on the engine, and switching means for making said additional regulating means effective when the engine is operating at a predetermined speed.

THELBERT L. WEYBREW. 

